Yeah I got all 3 classes as well. Did titan first, hes like 268ish (he had some awful RNG with milestones), then huntard, which is 280ish, then the lock which got to 290 last night. Did not go super hardcore either, just did the leveling shit, plus the basic milestones and mida on hunter and warlock, still have mida left on titan. Didnt even do nightfalls first week or any of the other quests. The titan had shit RNG with his milestones but the guns he got definitely helped hunter and warlock which were both like 240 ish after story was done.
I also did the lv 4-15 or 16 on titan then finish out story. IMO its best that way since you get sort of geared out for the stoy with some basic good blue weapons and the last 2-3 quests you get to 20 and get to use the good weapons from your first dude. Plus you get like 3-4 token turn ins on titan which will push you even further to 260+ just by handing them in.